Weitao LIU
,
Changchuan XIE
,
Michel Bellet
,
Herve
金属学报(英文版)
doi:10.1016/S1006-7191(08)60094-0
In order to improve the prediction accuracy of macrosegregation channel, an algorithm for dynamic remeshing is proposed. The basic idea is to generate fine elements near the liquidus isotherm. The norm of the gradient of solid fraction is used for piloting the remeshing in the mushy zone; whereas, the objective mesh size in the liquid is considered as a function of the distance to the liquidus isotherm. The efficiency of mesh adaptation is demonstrated by prediction of macrosegregation channel in a case of unidirectional solidification.
关键词:
Freckle
,
null
,
null
,
null
张长利
,
Michel Bellet
,
Manuel Bobadilla
,
沈厚发
,
柳百成
金属学报
doi:10.3724/SP.J.1037.2010.00286
开发了电势-热-力耦合有限元计算模型,该模型考虑了微合金低碳钢高温条件下的奥氏体γ和高温铁索体δ相变,建立了多相混合力学模型,描述了(δ+γ)两相混合区的力学行为.应用多场耦合计算模型对拉伸实验过程进行了数值模拟.实验及数值模拟结果表明,拉伸试样内存在较大径向及轴向温度梯度,该温度梯度导致试样内产生相体积分数的梯度分布,如高温铁素体相分数和液相分数的梯度分布,试样内产生非均匀变形,并且应力分布极不均匀.在进行实验钢高温力学本构方程的参数标定时,采用名义应力-应变的方法会导致较大误差,而基于数值模拟的方法则是十分有效及准确的,如本文所建立的数值模型.
关键词:
拉伸实验
,
微合金低碳钢
,
数值模拟
